Rational Pathways to Ordered Multianion Chalcogenides Using Retrosynthetic Crystal Chemistry

Mixed-anion chalcogenides make up a versatile class of materials with properties that can be fine-tuned for specific applications. While chalcogen anions (Q = S, Se, or Te) tend to form solid solutions in simple binary systems, ordering does occur in structures that have more than one unique anion site. Here, we use crystallographic analysis and hard-soft acid-base principles to predict the Wyckoff positions that secondary chalcogens will occupy in a range of single-anion hosts. The analysis serves as a guide for generating ordered sulfoselenide, selenotelluride, and sulfotelluride products in a predictable manner. The study focuses on ternary and quaternary systems with varying compositional and structural features, with an emphasis on 3D CsCu